Attenuation of Seismic Multiples in Very Shallow Water: An Application in Archaeological Prospection Using Data Driven Approaches

Round 1

Reviewer 1 Report

Review of the manuscript Attenuation of seismic multiples in very shallow water: an application in archaeological prospection using data-driven approaches by Michaela Schwardt et al.

 

I am a physicist working with various seismic techniques, including a small geoengineering scale, with some experience in multiple attenuation methods applied to industrial data. I have experience in advanced techniques like Multiple attenuation by Up-Down deconvolution applied to field data, and more typical (2D SRME, predictions) normally available in Vista software.

 

General info

The manuscript describes a detailed analysis of several, previously published multiple attenuation techniques, applied to atypical very shallow archaeological data. It discusses the pros and cons of each method, showing both synthetic examples and field data application.

 

The presented manuscript is well written and clearly structured. I am not a native speaker so I cannot evaluate the language, still I had no problem understanding it. The introduction is excellent, with a detailed review of literaturę and clearly defined research questions. Description of Methods is a bit long with many basic aspects that could be shortened. A very detailed synthetic study (Figures 3-8) is my major concern of this article. Field data are well presented and convincing, and the following discussion is well written.

 

Major problems:

1) synthetic study with perfectly defined seabed depth, source wavelet and the water velocity is poor (Figure 5). Such a case without noise should lead to perfect results for all methods in the industrial scale. I am not sure how changing scale to archaeological problems is influencing the quality, still with known parameters and without noise, all methods should work. (Figure 5) amount of artefacts for method A and B is overwhelming. What value of the stabilization parameter (epsilon)was used?

2) For SRME how many applications used in the synthetic test (Figure 4)? As I understand VISTA software a single use of SRME eliminates only the first-order multiple, and the procedure has to be repeated to impact further multiples.

3) Figure 6 and chapter 3.1.3 shows also very strong artefacts. Is that problem of small scale, near-field effects or poor stabilisation?

 

Small problems:

Eq. 6 how d was calculated? (in supplements A13 also unclear, need to follow the reference to understand it)

some of the Figures (like FIgure 3) are poor quality, still lit is easy to understand (or guess) the content

230: primaries -> primary

300: and are thus be masked by it -> and are masked by it

 

Besides of long and not convincing synthetic study, the whole manuscript shows a very interesting review of methods and an interesting discussion of how to use them in archaeological studies.

I recommend to publish it after small corrections and maybe a reduction.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

The work presents different methods to remove the multiple reflections from seismic reflections in shallow marine environments. The manuscript is clearly written with solid objectives. The research is based on synthetic modeling and field data to support the efficiency of the applied methods. The authors have made a substantial effort in modeling the geophysical problem and trying to propose different methodologies to clear the data from the multiple reflections. Below are some minor comments

1. The synthetic modeling results are extremely successful in a sense that they are "too good to be true". Did the authors try synthetic data that have been contaminated with different sources of noise to test the methodologies in the presence of noisy data?
2. The authors mention a drawback of the methodology in terms of increased computational and time resources to process and interpret the data. This is indeed extremely constructive and informative. However, I would also suggest to add a paragraph placing their approach in the wider context of archaeological prospection is shallow off-shore sites. It is known that basic goal of a geophysical survey in a submerged archaeological site is its extensive mapping with high resolution and possible extraction for the stratigraphy of the site. Since the authors present only results for 2D sections, the question that should be addressed is  why should someone choose the proposed methodology in contrast to other geophysical methods (electrical resistivity tomorgaphy or magnetic gradiometry) where the data collection is faster and processing is more simple. 
3. The statement in lines 29-30 is not entirely complete since there are relevant research efforts to approach this problem efficiently with very good results in archaeological prospection. See for example 

   Loke M.H., Lane J.W.L.Jr., 2004. Inversion of data from electrical resistivity imaging surveys in water-covered areas, Exploration Geophysics 35, 266-271 

   Passaro, S., 2010. Marine electrical resistivity tomography for shipwreck detection in very shallow water: a case study from Agropoli (Salerno, southern Italy). Journal of Archaeological Science 37, p.1989–1998. 

   Simyrdanis, K., Papadopoulos, N., Cantoro, G, 2016. Shallow off-shore archaeological prospection with 3-D electrical resistivity tomography: The case of Olous (modern Elounda), Greece. Remote Sensing, 8, 897.

4. The introduction has to include a paragraph with references to other geophysical methods applied in shallow submerged archaeological sites

 In principle I support the publication of the paper. The excellence of the authors is modeling and interpretation of the seismic data is beyond any doubt. My only concern lies on the actual applicability and routine employment of this methodology in archaeological prospection, which has to be adequately explained in the paper.

Author Response

Please see the attachmen

Author Response File: Author Response.pdf